Bull Nose Tail Stock center

[ducdon]

Anybody know off hand what the taper angle is on a Bull Nose center? I have a home made center I am converting to a Bull nose center. Centers are usually 60 degrees to work in a cut center. Since it will only be used to center pipe or tubing is there any reason I shouldn't make it 80 or 90 degrees???

 

[Dabbler]

I've seen BN centres wider than that - nearly 120 degrees. Use what works.

 

[PeterT]

Good question. Its almost like anything goes for supporting tubing. I'm guessing you would need to apply a slight chamfer on the ID so maybe one train of thought is 45-deg chamfer on the compound = 90-deg included angle for tail stock center? The center could be made quite compact & you don't need it to a point. I see these live centers that have plug-in tips. Are you adapting to that or thinking of a dead center or? Keep us informed what you decided & how it works. I have some tubing work coming up myself & haven't crossed that bridge.

 

[ducdon]

I decided on 80 degrees for very technical reasons. When I rotate the compound more than 40 degrees I bang my knuckles on the light standard.
OD is a bit over 2.375. I made the minor diameter so it would take over were my other one leaves off.

 

[RobinHood]

Nice job. That should work well for you.

 

[Dabbler]

very nice!

 

[Everett]

Yes, that is a very nice job on that one!

 

[PeterT]

Did you retrofit the new bull nose onto an an existing arbor make everything yourself?
I guess more what I'm wondering is whats under the lubrication nipple, like thrust bearing or twin roller bearing or....?
I'm thinking about a similar gadget but seems like the innards of live centers are pretty skookum surfaces & bearings.
OTOH, I'm using a dead center with a dab of grease

 

[ducdon]

Did you retrofit the new bull nose onto an an existing arbor make everything yourself?
I guess more what I'm wondering is whats under the lubrication nipple, like thrust bearing or twin roller bearing or....?
I'm thinking about a similar gadget but seems like the innards of live centers are pretty skookum surfaces & bearings.
OTOH, I'm using a dead center with a dab of grease

It was originally a student assignment from SAIT. The axle it turns on is a 1/2 X 2 inch steel dowel pin. It runs in a bronze bushing in the arbor. The grease fitting feeds a hole in the bushing. At the bottom of the hole in the arbor is a steel ball bearing that the back end of the axle seats against. The cone is press fit on the outer end of the axle. Not something I will use every day but for those occasions were I need something bigger it will suffice. The body of the arbor is free machining steel. Not very durable for hard use.